The present invention relates to a self-propelled, walk-behind rotary lawn mower and, more specifically, to a blade coupler assembly for use in attaching a cutting blade to the same.
Conventional walk-behind, rotary lawn mowers typically include a mower deck supported by multiple, e.g., four, wheels. In general, the top side of the deck forms an engine mounting surface to receive a prime mover (e.g., an internal combustion engine or an electric motor) while the underside of the deck forms a cutting chamber operable to house a cutting blade. The cutting blade is typically attached to a lower end of a vertical drive shaft, e.g., an engine crankshaft, which extends downwardly through the mower deck and into the cutting chamber. During operation, the drive shaft rotates the cutting blade at a speed sufficient to sever grass and other vegetation.
Although the cutting blade may attach directly to the crankshaft, many mowers use an intermediate blade coupling device between the cutting blade and the crankshaft. The coupling device may form a flanged hub to which the cutting blade is bolted. Examples of such coupling devices are found in U.S. Pat. Nos. 3,085,386 (Slemmons) and U.S. Pat. No. 4,307,558 (Bent et al.).
In addition to incorporating a coupling device, modem walk-behind mowers may also include a transmission to provide driving power to one or more of the wheels. The transmission typically receives power from a drive pulley which is also attached to the crankshaft, typically via a set screw, pin, or the like.
While more than adequate for their intended purposes, many of the current blade coupling devices and drive pulleys have drawbacks. For instance, numerous parts are often required to attach the blade coupling device and the drive pulley to the crankshaft. As a consequence, manufacturing/production costs may be higher than desired. Moreover, higher part counts may be perceived by the end user to equate with greater complexity with respect to assembly and/or maintenance aspects of the mower.
One design that addresses some of these concerns is illustrated in U.S. Pat. No. 3,157,978 (McMullen). This patent discloses a locking hub for a lawn mower blade. While directed to other aspects, e.g., positive locking of the blade and the incorporation of a friction washer, the ""978 patent illustrates incorporation of a V-belt groove on a flange member of the locking hub. However, certain aspects of ""978 locking hubxe2x80x94e.g., the large diameter flange member, the relatively deep blind bore formed therein, and the numerous pieces required to secure the bladexe2x80x94may still yield a coupling device having higher than desired cost.
U.S. Pat. No. 4,817,372 (Toda et al.) illustrates a blade holder utilizing a collar with a drive pulley. Once again, however, drawbacks remain, e.g., the machined collar and the multiple components necessary to secure the blade.
The present invention provides a blade coupler assembly which may include a blade/belt driver assembly operable to permit coupling of both a cutting blade and a drive belt to a drive shaft of a prime mover.
In one embodiment, a blade/belt driver assembly operable to couple a cutting blade and a drive belt to a lawn mower engine drive shaft is provided. The blade/belt driver assembly includes a tube having a first bore defined by a first diameter, where the first bore spans between a first longitudinal end and a second longitudinal end of the tube. A pulley is also included and is fixed to the tube such that at least a portion of the pulley abuts the first longitudinal end of the tube. The pulley has a second bore defined by a second diameter, wherein the second diameter is less than the first diameter. The blade/belt driver assembly further includes a blade receiver fixed to the tube such that the blade receiver abuts the second longitudinal end of the tube. The blade receiver has a third bore defined by a third diameter.
In another embodiment of the invention, a method for attaching a cutting blade and a drive belt to a lawn mower engine crankshaft is provided. The method includes sliding a blade/belt driver assembly over a first end of the engine crankshaft. In this embodiment, the blade/belt driver assembly includes a tube having a first bore defined by a first diameter, wherein the first bore spans between a first longitudinal end and a second longitudinal end of the tube. Also included is a pulley fixed to the tube such that at least a portion of the pulley abuts the first longitudinal end of the tube. The pulley includes a second bore defined by a second diameter, wherein the second diameter is less than the first diameter. The blade/belt driver assembly also includes a blade receiver fixed to the tube such that the blade receiver abuts the second longitudinal end of the tube. The blade receiver includes a third bore defined by a third diameter, the third bore having a centerline which is substantially coaxial with a centerline of the second bore. The method also includes positioning a first side of the cutting blade in an abutting relationship with the blade receiver, and passing a fastener through an opening in the cutting blade and through the third bore. The fastener is then threaded into a threaded hole located in the first end of the engine crankshaft.
In yet another embodiment of the invention, a lawn mower is provided. The mower includes a mower deck supported by a plurality of ground engaging wheels and defining a cutting chamber. Also included is a prime mover coupled to a first side of the mower deck, the prime mover having a crankshaft extending through the mower deck and terminating at a first end within the cutting chamber. A blade/belt driver assembly operable for interconnecting a cutting blade and a drive belt to the crankshaft is also included. The driver assembly includes a tube having a first bore defined by a first diameter, the first bore spanning between a first longitudinal end and a second longitudinal end of the tube. Also included is a pulley welded to the such tube such that at least a portion of the pulley abuts the first longitudinal end of the tube. The pulley has a second bore defined by a second diameter, wherein the second diameter is less than the first diameter. The first bore and the second bore are operable to receive the first end of the crankshaft. The driver assembly still further includes a blade receiver welded to the tube such that the blade receiver abuts the second longitudinal end of the tube, wherein the blade receiver has a third bore defined by a third diameter.
In still yet another embodiment, a blade coupler assembly operable to interconnect a cutting blade and a drive belt to an engine crankshaft of a self-propelled lawn mower is provided. The blade coupler assembly includes a blade/belt driver assembly and a fastener operable to secure the cutting blade and the blade/belt driver assembly to a first end of the engine crankshaft. The blade/belt driver assembly includes a tube having a first bore defined by a first diameter, wherein the first bore spans between a first longitudinal end and a second longitudinal end of the tube. A pulley is also included and is fixed to the tube such that at least a portion of the pulley abuts the first longitudinal end of the tube. The pulley has a second bore defined by a second diameter, wherein the second diameter is less than the first diameter and further wherein the first bore and the second bore are operable to slide over the first end of the engine crankshaft. The blade/belt driver assembly also includes a blade receiver fixed to the tube such that the blade receiver abuts the second longitudinal end of the tube. The blade receiver has a third bore defined by a third diameter, wherein a portion of the blade receiver is operable to abut a first side of the cutting blade.
The above summary of the invention is not intended to describe each embodiment or every implementation of the present invention. Rather, a more complete understanding of the invention will become apparent and appreciated by reference to the following detailed description and claims in view of the accompanying drawing.